1 // Copyright 2013 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef CHROME_BROWSER_MEDIA_MEDIA_DEVICE_ID_SALT_H_ 6 #define CHROME_BROWSER_MEDIA_MEDIA_DEVICE_ID_SALT_H_ 7 8 #include <string> 9 10 #include "base/memory/ref_counted.h" 11 #include "base/prefs/pref_member.h" 12 #include "components/pref_registry/pref_registry_syncable.h" 13 14 class PrefService; 15 16 // MediaDeviceIDSalt is responsible for creating and retrieving a salt string 17 // that is used for creating MediaSource IDs that can be cached by a web 18 // service. If the cache is cleared, the MediaSourceIds are invalidated. 19 // 20 // The class is reference counted so that it can be used in the 21 // callback returned by ResourceContext::GetMediaDeviceIDSalt. 22 class MediaDeviceIDSalt : public base::RefCountedThreadSafe<MediaDeviceIDSalt> { 23 public: 24 MediaDeviceIDSalt(PrefService* pref_service, bool incognito); 25 void ShutdownOnUIThread(); 26 27 std::string GetSalt() const; 28 29 static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry); 30 static void Reset(PrefService* pref_service); 31 32 private: 33 friend class base::RefCountedThreadSafe<MediaDeviceIDSalt>; 34 ~MediaDeviceIDSalt(); 35 36 // |incognito_salt_| is initialized in ctor on UI thread but only read 37 // on the IO thread. 38 std::string incognito_salt_; 39 mutable StringPrefMember media_device_id_salt_; 40 41 DISALLOW_COPY_AND_ASSIGN(MediaDeviceIDSalt); 42 }; 43 44 #endif // CHROME_BROWSER_MEDIA_MEDIA_DEVICE_ID_SALT_H_ 45